A PSA (Polymer Sustained Alignment) type liquid crystal display device has a polymer structure formed in a cell in order to control a pretilt angle of a liquid crystal molecule, and has been practically used as a next-generation liquid crystal display device due to the characteristics of high-speed responsiveness, high contrast, and the like.
The PSA type liquid crystal display device is a liquid crystal display device using a polymerizable compound-containing liquid crystal composition including a liquid crystal compound and a polymerizable compound, and is manufactured by polymerizing the polymerizable compound in a state where liquid crystal molecules are aligned by applying a voltage so as to fix the alignment of the liquid crystal molecules. In the process of polymerizing the polymerizable compound of the PSA type liquid crystal display device, the polymerization reaction rate of the polymerizable compound is very important for productivity. The adjustment of a pretilt angle influencing the response speed and contrast of the PSA type liquid crystal display device, or the adjustment of the residual amount of the polymerizable compound influencing reliability such as display unevenness or image persistence is also very important. Since the polymerization reaction rate of the polymerizable compound depends on the wavelength and irradiation intensity of an UV irradiation lamp, it has been required to develop a polymerizable compound-containing liquid crystal composition containing a polymerizable compound met specifications of the UV irradiation lamp. However, sufficient support has been difficult.
As an approach from a liquid crystal composition, there is introduced a technology of reducing a polymerization reaction rate by containing a liquid crystal compound having a terphenyl ring (PTL 1). However, when the liquid crystal compound having a terphenyl ring is used, it may make an influence on reliability such as display unevenness or image persistence due to a decrease in VHR.
As described above, a polymerizable compound-containing liquid crystal composition satisfying the adjustment of the polymerization reaction rate adapted for the UV irradiation lamp, the high-speed responsiveness and high contrast of a liquid crystal display device, and the display unevenness and image persistence of a liquid crystal display device has been required, and a liquid crystal display device using the polymerizable compound-containing liquid crystal composition has also been required.